//Checks that the proof graph has no issues
void ProofGraph::checkProof()
{
//Visit graph from sink keeping track of edges and nodes
std::deque<ProofNode*> q;
ProofNode* n;
q.push_back(graph[root]);
do
{
n=q.front();
q.pop_front();
//End current level, change level and set new end
if(!visited[n->getId()])
{
checkClause(n->getId());
if(n->getAnt1()!=NULL || n->getAnt2()!=NULL)
{
if(n->getAnt1()!=NULL) q.push_back(n->getAnt1());
if(n->getAnt2()!=NULL) q.push_back(n->getAnt2());
}
visited[n->getId()]=true;
}
}
while(!q.empty());
visited.reset();
}
//
// Check if a formula is a clause
//
bool Cnfizer::checkClause( Enode * e, set< enodeid_t > & check_cache )
{
assert( e );
if ( e->isLit( ) )
{
check_cache.insert( e->getId( ) ); // Don't check again
return true;
}
if ( !e->isOr( ) )
return false;
if ( check_cache.find( e->getId( ) ) != check_cache.end( ) ) // Already visited term
return true;
bool is_clause = true;
for ( Enode * list = e->getCdr( ) ;
list != egraph.enil && is_clause ;
list = list->getCdr( ) )
is_clause = checkClause( list->getCar( ), check_cache );
if ( !is_clause )
return false;
check_cache.insert( e->getId( ) ); // Don't check again
return true;
}
//
// Check if a formula is a conjunction of clauses
//
bool Cnfizer::checkConj( Enode * e, set< enodeid_t > & check_cache )
{
if ( !e->isAnd( ) )
return false;
if ( check_cache.find( e->getId( ) ) != check_cache.end( ) ) // Already visited term
return true;
Enode * list = e->getCdr( );
for ( ; list != egraph.enil ; list = list->getCdr( ) )
{
Enode * arg = list->getCar( );
if( !checkConj( arg, check_cache ) && !checkClause( arg, check_cache ) )
return false;
}
check_cache.insert( e->getId( ) );
return true;
}
//
// Check whether a formula is in cnf
//
bool Cnfizer::checkCnf( Enode * formula )
{
set< enodeid_t > check_cache;
bool res = checkConj( formula, check_cache ) || checkClause( formula, check_cache );
return res;
}
